Axial-flux induction motor pump

ABSTRACT

A pump comprises a housing partially defining a cavity, an impeller arranged in cavity, the impeller including a first disk, and a vane arranged on the first disk, the impeller operative to rotate about a rotational axis, a first stator core arranged on the housing, windings arranged on the first stator core, and a first inlet defined by the housing, wherein the first inlet, the impeller, and the housing partially define a fluid flow path.

TECHNICAL FIELD

The present disclosure relates to pumps, and particularly to anaxial-flux induction motor driven centrifugal pump.

BACKGROUND

Centrifugal pumps include a housing with an impeller that is driven by aprime mover to rotate in the housing. Fluid typically enters the pumpimpeller axially through a suction side intake and is accelerated toflow radially. The housing chamber acts as a diffuser that deceleratesthe flow of the fluid and increases the pressure of the fluid, which isdischarged from an outlet on the pressure side of the pump.

SUMMARY

According to an embodiment, a pump comprises a housing partiallydefining a cavity, an impeller arranged in cavity, the impellerincluding a first disk, and a vane arranged on the first disk, theimpeller operative to rotate about a rotational axis, a first statorcore arranged on the housing, windings arranged on the first statorcore, and a first inlet defined by the housing, wherein the first inlet,the impeller, and the housing partially define a fluid flow path.

According to another embodiment, a pump comprises a housing partiallydefining a cavity, an impeller arranged in cavity, the impellerincluding a first disk, a second disk, and a vane arranged between thefirst disk and the second disk, the impeller operative to rotate about arotational axis, a first stator core arranged on the housing such that aportion of the first stator core partially defines the cavity, windingsarranged on the first stator core, and a first inlet defined by thehousing, wherein the first inlet, the impeller, and the housingpartially define a fluid flow path.

According to yet another embodiment, a pump comprises a housingpartially defining a cavity, an impeller arranged in cavity, theimpeller including a first disk, and a vane arranged on the first disk,the impeller operative to rotate about a rotational axis, a first statorcore arranged on the housing such that a portion of the first statorcore partially defines the cavity, windings arranged on the first statorcore, and a first inlet defined by the housing, wherein the first inlet,the impellor, and the housing partially define a fluid flow path.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments and features of the present disclosure will now bedescribed by way of example only, and with reference to FIGS. 1 to 6, ofwhich:

FIG. 1 illustrates a cut-away view along the line A-A of FIG. 2 of anexemplary embodiment of an axial-flux induction motor pump.

FIG. 2 illustrates a side view of the pump of FIG. 1.

FIG. 3 illustrates an alternate exemplary embodiment of a pump.

FIG. 4 illustrates another alternate exemplary embodiment of a pump.

FIG. 5 illustrates an example of a fluid flow path.

FIG. 6 illustrates an alternate embodiment of a pump that includes twofluid inlets.

DETAILED DESCRIPTION

Previous centrifugal pumps often included a prime mover such as anelectric motor or engine that was coupled to the impeller via a driveshaft. Such pumps were large and heavy, and used bushings and seals thatoften needed maintenance.

Some previous centrifugal pumps integrated the pump and motor where theimpeller contained permanent magnets such that the impeller acted as therotor for a brushless direct current (DC) motor. Such pumps producedhigh axial attractive forces (at zero current state) between the statorand impeller that caused difficulties in practical assembly of thepumps. The magnetic impeller attracted unwanted ferromagnetic debris.The pumps also used more complicated electronics to control the pumpmotor.

FIG. 1 illustrates a cut-away view along the line A-A (of FIG. 2) of anexemplary embodiment of an axial-flux induction motor pump 100. The pump100 is a centrifugal type pump having a fluid inlet 102 thatcommunicates through a housing 104. An impeller 106 is arranged in thehousing 104 and is arranged to rotate around an axis of rotation 101.The impeller includes vanes 108 arranged between a first disk 110 and asecond disk 112 that secure the vanes 108. An electrically conductivematerial 114 is arranged on the first disk 110. A stator core 116 isarranged proximate to the conductive material 114. Windings 118 arearranged on the stator core 116. The stator core 116 and the conductivematerial 114 define a gap having a gap width (g). In the illustratedembodiment, the stator core 116 is arranged in the housing 104 such thatan inner surface (active surface) 119 of the stator core 116 isproximate to the conductive material 114. The stator core 116 passesthrough the housing 104 and partially defines the chamber 120 with thehousing 104. In the illustrated embodiment the stator core 116 contactsand partially defines the flow path of the fluid.

In the illustrated embodiment, the housing 104 may be formed from anysuitable material such as, for example, a plastic or polymer material, anonmagnetic material such as bronze, aluminium, titanium or ceramic, ora ferromagnetic material such as, for example steel or nickel. The firstdisk 110 is formed from a suitable ferromagnetic material such as, forexample, steel, nickel, or another ferromagnetic alloy. The second disk112 in the illustrated embodiment, may be formed from any suitablematerial such as, for example, a plastic or polymer material, or ametallic or ceramic material. In the illustrated embodiment, the seconddisk 112 may be formed from similar or dissimilar materials as the firstdisk 110.

The conductive material 114 arranged in contact with the first disk 110,and may include a conductive material such as, for example, copper orsilver. The stator core 116 may be a single phase or a poly-phase, andmay be formed from, for example, a laminated or sintered powderferromagnetic material. The windings 118 are formed from, for example,copper or aluminium wire that may be wound about the stator core 116.

In operation, the first disk 110 conducts both electric current andmagnetic flux. Eddy currents induced in the first disk 110 interact withthe stator magnetic field to produce electromagnetic torque. The torqueis applied to the first disk 110, which rotates the impeller 106 aboutthe rotational axis 101. The rotation of the impeller 106 draws fluidthrough the fluid inlet 102, and increases the velocity and pressure ofthe fluid as the fluid flows radially outward. The fluid is dischargedfrom the pump 100 via an outlet 202 (described below in FIG. 2).

Higher torque is achieved by increasing the current in the first disk110 and the magnetic flux density in the gap 103 between the first disk110 and the stator core 116. The current in the first disk 110 may beincreased by reducing the impedance for eddy currents in the first disk110. The impedance for eddy currents in the first disk 110 can bedecreased by arranging a conductive material 114 having a relativelyhigher conductivity than the conductivity of the first disk 110 on anouter surface 105 of the first disk 110 such that the conductivematerial 114 is disposed between the first disk 110 and the stator core116. The conductive material 114 may include, for example, copper orsilver, and may be, for example, arranged as a coating on the first disk110 or may be fabricated by securing a disk of the conductive material114 to the first disk 110. The arrangement of the conductive material114 on the disk 110 need not cover the entire outer surface 105 of thedisk 110. In alternate embodiments, for example, the conductive material114 may be arranged as bands proximate to edges of the first disk 110.Radial or skewed slots may also be arranged in the first disk 110 toreduce the impedance for eddy currents of the first disk 110 in otheralternate embodiments.

FIG. 2 illustrates a side view of the pump 100. The windings 118 areshown arranged about the stator core 116. In FIG. 2 some of the windings118 are not shown for clarity. In this regard, in the exemplaryembodiment, the windings 118 are arranged axially about the axis ofrotation 101 on the stator core 116. FIG. 2 illustrates the fluid outlet202, which is communicative with the chamber 120.

FIG. 3 illustrates an alternate exemplary embodiment of a pump 300. Thepump 300 is similar to the pump 100 (of FIG. 1) described above. Thepump 300 includes an additional stator core 116 b and additionalwindings 118 b arranged on a side of the impeller 106 opposing thestator core 116 a and windings 118 a. A disk 110 b that is similar tothe disk 110 a is arranged proximate to the stator core 116 b. Aconductive material 114 b is arranged on the second disk 110 b. Theoperation of the pump 300 is similar to the operation of the pump 100described above.

FIG. 4 illustrates another alternate exemplary embodiment of a pump 400.The pump 400 is similar to the pump 100 (of FIG. 1) however; the statorcore 116 is mounted on an outer surface 401 of the housing 104. In otheralternate embodiments, the pump 300 (of FIG. 3) may include stator cores116 a and/or 116 b arranged on the outer surface of the housing 104 ofpump 300 in a manner similar to the pump 400.

FIG. 5 illustrates an example of the fluid flow path 501 of pump 500similar to the pumps described above. In the illustrated embodiment thefluid flows through the inlet 102 and radially outward from the axis ofrotation 101 of the impeller 106. The fluid flows through the gap 103partially defined by the housing 104, the stator core 116 and theconductive material 114.

FIG. 6 illustrates an alternate embodiment of a pump 600 that includestwo fluid inlets, a first fluid inlet 102 and a second fluid inlet 602opposing the first fluid inlet 102. The fluid flow path 601 is partiallydefined by the first fluid inlet 102 and the second fluid inlet 602. Thearrangement of the inlets 102 and 602 of FIG. 6 may be used in any ofthe embodiments described above.

The embodiments of a centrifugal pump described above offer a low cost,compact, high speed pump that may be used in a number of fluid systems.The pump avoids using permanent magnets, which attract unwantedferromagnetic debris. The pump has low susceptibility to electromagneticinterference, and may be assembled easily.

Although the figures and the accompanying description describeparticular embodiments, it is to be understood that the scope of thisdisclosure is not to be limited to such specific embodiments, and is,instead, to be determined by the scope of the following claims.

What is claimed is:
 1. A pump comprising: a housing partially defining acavity; an impeller arranged in cavity, the impeller including a firstdisk, and a vane arranged on the first disk, the impeller operative torotate about a rotational axis; a first stator core arranged on thehousing; windings arranged on the first stator core; and a first inletdefined by the housing, wherein the first inlet, the impeller, and thehousing partially define a fluid flow path.
 2. The pump of claim 1,further comprising a conductive material arranged on a surface of thefirst disk such that the conductive material is disposed between thefirst disk and the first stator core such that the conductive materialand the first stator core partially define a gap therebetween.
 3. Thepump of claim 1, wherein further comprising a second stator corearranged on the housing, wherein the second stator core is arrangedcircumferentially about the rotational axis.
 4. The pump of claim 1,wherein the first disk includes a ferromagnetic material that isconductive to electric current and magnetic flux.
 5. The pump of claim3, wherein the impeller further includes a second disk arranged suchthat the vane is disposed between the second disk and the first disk,the second disk including a ferromagnetic material that is conductive toelectric current and magnetic flux.
 6. The pump of claim 5, furthercomprising a conductive material arranged on a surface of the seconddisk such that the conductive material is disposed between the seconddisk and the second stator core such that the conductive material andthe first second core partially define a gap therebetween.
 7. The pumpof claim 2, wherein the conductive material has a higher conductivitythan the first disk.
 8. The pump of claim 1, further comprising a secondinlet defined by the housing, wherein the second inlet partially definesthe fluid flow path.
 9. The pump of claim 1, wherein the housingincludes an outlet communicative with the cavity, the outlet partiallydefining the fluid flow path.
 10. A pump comprising: a housing partiallydefining a cavity; an impeller arranged in cavity, the impellerincluding a first disk, a second disk, and a vane arranged between thefirst disk and the second disk, the impeller operative to rotate about arotational axis; a first stator core arranged on the housing such that aportion of the first stator core partially defines the cavity; windingsarranged on the first stator core; and a first inlet defined by thehousing, wherein the first inlet, the impeller, and the housingpartially define a fluid flow path.
 11. The pump of claim 10, furthercomprising a conductive material arranged on a surface of the first disksuch that the conductive material is disposed between the first disk andthe first stator core such that the conductive material and the firststator core partially define a gap therebetween.
 12. The pump of claim10, wherein further comprising a second stator core arranged on thehousing, wherein the second stator core is arranged circumferentiallyabout the rotational axis.
 13. The pump of claim 10, wherein the firstdisk includes a ferromagnetic material that is conductive to electriccurrent and magnetic flux.
 14. The pump of claim 12, wherein the seconddisk includes a ferromagnetic material that is conductive to electriccurrent and magnetic flux.
 15. The pump of claim 12, further comprisinga conductive material arranged on a surface of the second disk such thatthe conductive material is disposed between the second disk and thesecond stator core such that the conductive material and the secondstator core partially define a gap therebetween.
 16. A pump comprising:a housing partially defining a cavity; an impeller arranged in cavity,the impeller including a first disk, and a vane arranged on the firstdisk, the impeller operative to rotate about a rotational axis; a firststator core arranged on the housing such that a portion of the firststator core partially defines the cavity; windings arranged on the firststator core; and a first inlet defined by the housing, wherein the firstinlet, the impeller, and the housing partially define a fluid flow path.17. The pump of claim 16, further comprising a conductive materialarranged on a surface of the first disk such that the conductivematerial is disposed between the first disk and the first stator coresuch that the conductive material and the first stator core partiallydefine a gap therebetween.
 18. The pump of claim 16, wherein furthercomprising a second stator core arranged on the housing, wherein thesecond stator core is arranged circumferentially about the rotationalaxis.
 19. The pump of claim 16, wherein the first disk includes aferromagnetic material that is conductive to electric current andmagnetic flux.
 20. The pump of claim 18, wherein the impeller furtherincludes a second disk arranged such that the vane is disposed betweenthe second disk and the first disk, the second disk including aferromagnetic material that is conductive to electric current andmagnetic flux.